A month and a half ago, Nature published the article:
A prebiotically plausible scenario of an RNA–peptide world
My question: plausible really? Here goes the narrative:
The RNA world concept is one of the most fundamental pillars of the origin of life theory. It predicts that life evolved from increasingly complex self-replicating RNA molecules. The question of how this RNA world then advanced to the next stage, in which proteins became the catalysts of life and RNA reduced its function predominantly to information storage, is one of the most mysterious chicken-and-egg conundrums in evolution. Here we show that non-canonical RNA bases, which are found today in transfer and ribosomal RNAs and which are considered to be relics of the RNA world, are able to establish peptide synthesis directly on RNA. The discovered chemistry creates complex peptide-decorated RNA chimeric molecules, which suggests the early existence of an RNA–peptide world from which ribosomal peptide synthesis may have emerged. The ability to grow peptides on RNA with the help of non-canonical vestige nucleosides offers the possibility of an early co-evolution of covalently connected RNAs and peptides which then could have dissociated at a higher level of sophistication to create the dualistic nucleic acid–protein world that is the hallmark of all life on Earth.
How plausible is this scenario? First of all, we are talking about the origin of the most complex, most sophisticated molecular machine known in biology: The ribosome. The smallest known cytoplasmic ribosome is found in prokaryotic cells; these ribosomes contain over 4,000 RNA nucleotides and over 50 proteins. Ribosomes have more complex functions than virtually any other enzyme, so it is not surprising that ribosomes have a unique and more complicated structure that is present in all organisms.
If we suppose that the first universal common ancestor was the most primitive cell, then we can resort to bacteria, which are less complex than eukaryotic cells, or archaea. The thing is:
In bacteria, transcription and translation are linked in time and space. Unlike in eukaryotes, where transcription and translation occur in separate cellular compartments, in bacteria, these two processes are spatially and temporally coupled.
transcription and translation is an interdependent processes, and so, explaining its origin becomes much more complicated. BOTH processes have to be explained. RNA polymerase is another ultrasophisticated machine extant in all life forms, and so, life-essential as well.
Suggesting that some random RNA-peptides would by luck develop in such highly efficient, sophisticated nano-machines is pure pseudo-scientific gobbledygook. Unless a superintelligent creator was involved, such systems would never come to exist. Any other assertion is just plain irrational.
I have not enough faith to be an atheist.